CNN) -- Workers at a Texas state school for mentally handicapped adults are believed to have been staging a "fight club" among residents, encouraging them to physically battle one another, police told CNN Tuesday.

A cell phone containing videos of the alleged abuse at the Corpus Christi State School in Corpus Christi, Texas, was turned over to police last week, and authorities are expecting to file arrest warrants this week, Corpus Christi police Capt. Tim Wilson told CNN.

The incidents are believed to have taken place in a school dormitory, Wilson said.

"This has been going on for some time," Wilson said. "That is what makes this an exceptional case. It is not the workers abusing the clients, so to speak. The workers are not hitting them, but they are allowing these clients to fight with each other, thereby endangering their well-being."

"These people are charged with the care and custody of these clients, and they are exploiting (them)," he said.

Those involved will likely face charges of injury of a disabled person, Wilson said. The charge's severity can range up to a third-class felony, depending on the extent of a person's involvement, he said. The actual charges, however are left up to the Nueces County District Attorney, which is participating in the investigation along with the Texas Inspector General's Office, he said.

Seven school employees have been placed on paid emergency leave by the Texas Department of Aging and Disability Services, according to spokeswoman Cecilia Fedorov. Some former workers also will be interviewed, authorities said.

Fedorov said the agency received a phone call Friday from the state Department of Family and Protective Services, saying they had been alerted to the situation by police and were opening an investigation into possible abuse or neglect.

The employees on leave cannot come on to campus, but must sign in at the gate every day they are on leave, Fedorov said.

State officials are awaiting the outcome of the investigation to determine whether they should take further action, she said.

Wilson said Corpus Christi police received the cell phone a week ago, when a citizen found it and gave it to an officer working security at a hospital. The officer looked at several of the videos, then gave the phone to the police's forensic unit for analysis. More videos were found in the phone's memory.

"It appears it was some sort of a fight club," Wilson said. Twenty videos were found on the phone, with dates going back about a year. All the videos featured the school's "clients," who are severely mentally handicapped, he said.

On the videos, "they (the clients) are not upset like they are being forced," Wilson said. "They are being more goaded into it. There's a lot of voices on there from workers ... saying, 'Look at that, ha ha' ... laughing, stuff like that."

No clients are seen crying, upset or injured on the videos, he said, but no workers are seen stopping the fighting.

"The fighting entails pushing, wrestling and some shoving," Wilson said. Police do not believe anyone was seriously injured, he said, but the investigation is ongoing.

"Four or five clients have been identified and at least five workers, possibly as many as 10," he said. "Some are more active in staging the fights, and some others passively stand around not doing anything."

The clients are all adult males, ranging in age from their late teens into their 30s, he said. As part of the investigation, the Inspector General's office has interviewed some of the clients, Wilson said.

Asked whether the school had previously been investigated for abuse, he said, "This is the exception. Over the years, we have had isolated instances of abuse we have investigated. Every once in a while, the school itself would report a case, but this appears to be organized."

Police believe, based on the videos, the "fight club" was confined to one dormitory, he said.